If I read your post correctly (hey, gotta be a first time for everything, right?), you just want to wax philosophic on the theories/applications/benefits/shortcomings of both, correct? Not necessarily on just the Contour platform (which comes with two different engines).
Personally I prefer turbos for pretty much any application; however, like anything developed by man there are variables all over the place. Some engines respond really well to positive displacement blowers and some like centrifugal blowers.
Every engine is designed differently and each has its own inherent strengths and weaknesses. Having said that I wish I had turbos on both my cars.

I think it all depends on your application and intended use for the car.

Now owner of 0 SVT's. my web page